Recent dental treatment often employs a crown restorative material formed of a sintered zirconia block, glass block, or resin block processed by means of CAD/CAM, in order to repair a lost part of a tooth damaged, for example, by dental caries. Sintered bodies of zirconia are white; thus, a crown restorative material formed of a sintered body of zirconia is inferior to natural teeth in aesthetic quality. Sintered zirconia blocks, glass blocks, and resin blocks can be colored indeed, but adjustment of the color tone of these blocks to a desired one requires the use of many kinds of colorants having different color tones. One possible approach for reproducing the color tone of natural teeth is to use a block having layers of different color tones; however, exact reproduction of the color tone of natural teeth is difficult. Under these circumstances, further studies have been made on methods for adjusting the color tone of the surfaces of the crown restorative materials as mentioned above.
For example, Patent Literature 1 proposes: a method for color correction of replacement teeth or tooth surfaces, the method including application of photocurable corrective colors including: matrix monomers including bisphenol-A-diglycidyl acrylate, urethane dimethacrylate, and triethylene glycol dimethacrylate; a filler mixture of quartz, metal oxides, and dental glass; an initiator; and a slight amount of dental pigments. Patent Literature 1 also proposes a color kit for color correction.
Furthermore, treatment of natural tooth surfaces for maintaining the aesthetic quality of the surfaces has been previously studied.
For example, Patent Literature 2 proposes a dental coating kit that exhibits good bonding to teeth, with the main aim of preventing staining and discoloration of teeth, particularly staining and color return of bleached teeth, the dental coating kit including: a primer composition including an acid group-containing polymerizable monomer (a), water (b), and a water-soluble solvent (c); and a surface smoothing composition including a polyfunctional polymerizable monomer (0, a volatile solvent (g), and a photopolymerization initiator (h).